1. Field of the Invention:
The present invention relates to a yarn splicing apparatus for spun yarns in which jet air is applied to the overlapped yarn ends.
2. Prior Art:
It is usually performed that two yarn ends are spliced to each other by causing a compressed fluid to act on the yarn end parts placed one above the other. That is, two yarn ends are first inserted in a yarn splicing hole in such a way as they direct in the directions opposite to each other. By injecting compressed air into the yarn splicing hole, the overlapped parts of those two yarn ends are then vibrated or whirled, so that filaments of the yarn end parts are entangled to make yarn splicing. One example of this yarn splicing apparatus is disclosed in U.S. Pat. No. 4,263,775.
According to such yarn splicing, there can be attained many advantages as follows. The yarn thickness at the formed joint is as much as about 1.4 times a yarn as compared with that the thickness of conventional mechanical knots, such as fisherman's knot or weaver's knot is three times a yarn. Also, it is possible to obtain a joint without including a knot, and the knitting and weaving process encounters a less possibility of yarn breakage. Further, the woven goods are free of knots in their appearance and hence have high quality.
On the other hand, there has accompanied with a problem in the point of yarn strength. Span yarns such as chemical synthetic fibers, wool, etc. have a single fiber with a larger length (50-100 mm) relative to that of cotton (30-50 mm). In such yarns which are generally calls as long fibers, the yarns or fibers constituting each yarn have the smooth surface and small friction resistance, so that simple twisting has resulted the insufficient yarn strength. Differently stated, although the leading end parts of yarn ends are mixedly twined with each other depending on the position of fluid injection, the central parts of the joint are entangled in such a condition that the two yarns are distinguishable. As a result, the joint has the less yarn strength. Alternatively, the central parts of the joint are mixed with each other into the form of one yarn, but there cause the so-called horn portions at both ends, i.e., the leading end parts of both yarn ends are not twined and separated from each other. Also in this case, the yarn strength becomes less because it depends on the yarn strength in the central parts only.